tag:theconversation.com,2011:/es/topics/ear-infections-42036/articlesEar infections – The Conversation2022-09-30T12:27:25Ztag:theconversation.com,2011:article/1892132022-09-30T12:27:25Z2022-09-30T12:27:25ZSummer swimming season may be over, but you can still get swimmer’s ear – and you don’t even need to go in the water<figure><img src="https://images.theconversation.com/files/487181/original/file-20220928-18493-p69mat.jpg?ixlib=rb-1.1.0&rect=7%2C7%2C5126%2C3410&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Both children and adults are susceptible to the ear infection known as "swimmer's ear."</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/female-swimmer-wearing-a-bathing-cap-and-goggles-royalty-free-image/57434909?adppopup=true">Kay Blaschke/Stock4B-RF via Getty Images</a></span></figcaption></figure><p>Many forms of ear infections strike children and adults alike, but among the most common is <a href="https://doi.org/10.1093/pch/18.2.96">acute otitis externa</a>, also known as swimmer’s ear.</p>
<p>About 10% of Americans will <a href="https://www.ncbi.nlm.nih.gov/books/NBK279353/">experience swimmer’s ear during their lifetimes</a>. Adults are <a href="https://doi.org/10.3238/arztebl.2019.0224">affected more commonly</a>, and children only rarely, generally ages 5 to 12. </p>
<p>But you <a href="https://www.pennmedicine.org/updates/blogs/health-and-wellness/2018/august/swimmers-ear#:%7E:">don’t have to be swimming</a> to get swimmer’s ear. Go out jogging or walking, or do yardwork on a hot day, and moisture from perspiration can drip in your ear. However, the occurrence <a href="https://doi.org/10.3238/arztebl.2019.0224">increases fivefold in swimmers</a> – thus the reason the condition came to be called “swimmer’s ear.” It also occurs more frequently in tropical climates because of humidity and higher temperatures. </p>
<p>As doctors who specialize in ear problems, <a href="https://ent.ufl.edu/faculty-staff/faculty/rex-haberman-md/">we are actively involved</a> in <a href="https://ent.ufl.edu/faculty-staff/faculty/thomas-schrepfer-md/">research and clinical treatment</a> for children and adults struggling with ear, nose and throat problems. Practicing in the state of Florida, we’ve certainly seen our share of patients with swimmer’s ear.</p>
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<figcaption><span class="caption">If left untreated, swimmer’s ear could cause temporary hearing loss along with bone and cartilage damage.</span></figcaption>
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<h2>Causes and symptoms of swimmer’s ear</h2>
<p>Swimmer’s ear is an infection in the external ear canal, the tube leading from the ear opening to the eardrum. Typically, swimmer’s ear occurs only in one ear, and sometimes the eardrum itself is affected. Moisture trapped in the canal leads to a break in the skin barrier and <a href="https://www.nhsinform.scot/illnesses-and-conditions/ears-nose-and-throat/otitis-externa#causes-of-otitis-externa">creates an opening for certain bacteria types</a> to enter or existing ones to overgrow. </p>
<p>One of these culprits is the bacterium <em>Pseudomonas aeruginosa</em>, which is <a href="https://www.cdc.gov/hai/organisms/pseudomonas.html">present in soil and water</a> throughout the world. These bacteria favor moist areas, such as sinks, toilets, inadequately chlorinated swimming pools and hot tubs, as well as outdated or inactivated antiseptic solutions.</p>
<p>If you have the infection, you’ll know it. Symptoms generally appear a few days after infection. The main symptom of swimmer’s ear <a href="https://kidshealth.org/en/parents/swimmer-ear.html">is severe pain</a> and discomfort.
It’s particularly noticeable when the outer ear is tugged, or by touching the tragus – that’s the small bump at the front of your ear. Other symptoms include itchiness inside the ear, redness, swelling and drainage. A feeling of fullness, or the perception of a plugged ear, may also occur, along with disturbed balance and temporary hearing loss. </p>
<h2>Predisposition to swimmer’s ear</h2>
<p>Numerous factors can <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/swimmers-ear">predispose someone to swimmer’s ear</a>. They include a narrow ear canal, and skin diseases such as eczema or psoriasis. In addition, individuals wearing ear plugs, <a href="https://stvincents.org/about-us/news-press/news-detail?articleid=34511#">ear buds</a> or <a href="https://www.mayoclinic.org/diseases-conditions/swimmers-ear/symptoms-causes/syc-20351682">hearing aids</a> may be at an increased risk. Diabetics may also be <a href="https://doi.org/10.1016/j.amjoto.2016.04.005">more prone to the infection</a>. </p>
<p>Swimmer’s ear can also come from something getting stuck inside the ear, excessive ear cleaning or contact with chemicals in hair dye or hairspray. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/485738/original/file-20220920-11468-awmqty.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="This illustration, depicting both the outer and inner ear, shows how the infection from swimmer's ear has narrowed the ear canal." src="https://images.theconversation.com/files/485738/original/file-20220920-11468-awmqty.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/485738/original/file-20220920-11468-awmqty.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/485738/original/file-20220920-11468-awmqty.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/485738/original/file-20220920-11468-awmqty.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/485738/original/file-20220920-11468-awmqty.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/485738/original/file-20220920-11468-awmqty.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/485738/original/file-20220920-11468-awmqty.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">An illustration showing inflammation and narrowing of the ear canal.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/swimmers-ear-otitis-externa-royalty-free-illustration/1003084366?adppopup=true">ttsz/iStock via Getty Images Plus</a></span>
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<h2>Diagnosis and treatment</h2>
<p>Swimmer’s ear is diagnosed after a health care provider has gathered a thorough history and examined the inside of the ear. The ear canal will typically look red, swollen and moist. There is also a possibility of fluid drainage or the appearance of scaly, shedding skin. Depending on the degree of swelling, the eardrum may be hard to see. A sample of fluid may be removed from the ear and sent to a lab to look for bacteria or fungus.</p>
<p>Eardrops are commonly <a href="https://www.mayoclinic.org/diseases-conditions/swimmers-ear/diagnosis-treatment/drc-20351688#:%7E:">used to treat swimmer’s ear</a>. These drops often contain antibiotics to kill the infection and steroids to stop the swelling.</p>
<p>One such eardrop is <a href="https://www.webmd.com/drugs/2/drug-76594/ciprodex-otic-ear/details">Ciprodex</a>. It contains ciprofloxacin, an antibiotic, and dexamethasone, a powerful steroid. Patients will need to place about four to five drops in the infected ear canal twice a day for seven to 10 days. </p>
<p>Another commonly prescribed drop is <a href="https://www.webmd.com/drugs/2/drug-63597/floxin-otic-ear/details">Floxin</a>, which contains an antibiotic but not a steroid. It is commonly prescribed in less swollen but still infected ears. </p>
<p>Other drop preparations include <a href="https://www.webmd.com/drugs/2/drug-3715-8196/cortisporin-otic-ear/neomycin-polymyxin-hydrocortisone-suspension-otic/details">Cortisporin</a>, which contains a commonly used combination of neomycin and polymyxin B, as well as hydrocortisone. However, neomycin is also damaging to the inner ear, so doctors nowadays often turn to Ciprodex or Floxin.</p>
<p>In some cases, the ear canal is too swollen for drops to reach the infected area, so the physician may place a wick or stent in the ear canal to keep it open. This will usually be left in place for three to five days until removed by the doctor, although occasionally the wick falls out once the swelling subsides. Usually, after 10 days the infection is resolved and the ear canal skin returns to normal. </p>
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<figcaption><span class="caption">Don’t try to get the water out with a Q-tip.</span></figcaption>
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<h2>Managing a persistent infection</h2>
<p>Sometimes swimmer’s ear may not resolve after seven to 10 days of treatment with eardrops. Oral antibiotics are typically recommended if the infection <a href="https://my.clevelandclinic.org/health/diseases/8381-swimmers-ear-otitis-externa">has spread beyond the ear canal</a> or in patients with poorly controlled diabetes. Hospitalization for swimmer’s ear is rarely necessary; however, complications that can occasionally lead to hospitalization include fever, worsening discharge, extensive narrowing of the ear canal or failure of previous treatments.</p>
<p>Among the <a href="https://www.webmd.com/cold-and-flu/ear-infection/get-water-out-of-ear">precautions you can take</a> to prevent swimmer’s ear: Keep the ear canal dry. Tip your head to one side to help the water drain. Use a soft towel or cloth, or gently use a hair dryer near it. If the self-cleansing mechanism of the ear canal is impaired, then the ear canal should be cleansed by a physician.</p>
<p>Since most bacteria prefer a <a href="https://www.verywellhealth.com/ph-balance-significance-function-associated-conditions-5205825#:%7E:">pH-neutral environment</a>, reducing the pH in the ear canal can prevent bacterial overgrowth. A homemade liquid tincture can be mixed from a solution of half rubbing alcohol and half distilled white vinegar. The alcohol combines with the water in the ear and then evaporates. This removes the water while the acidity of the vinegar keeps bacteria from growing. </p>
<p>Two to three drops are usually sufficient and can be applied as a preventive measure soon after the ear has been exposed to moisture. This liquid solution is not a replacement for medical treatment of an actual ear infection and is meant to be used only in people who are prone to such infections because of prolonged or frequent exposure to moisture. </p>
<p>Also, it is important to differentiate swimmer’s ear from a <a href="https://kidshealth.org/en/parents/otitis-media.html">middle ear infection</a>, the most frequent reason for the use of antibiotics in children under age 5. <a href="https://theconversation.com/a-pediatrician-explains-a-spike-in-ear-infections-this-summer-after-covid-19-restrictions-lifted-166461">Middle ear infections</a> are usually associated with a viral upper respiratory infection, and they are more often seen during fall and winter, when influenza and cold viruses are more prevalent.</p><img src="https://counter.theconversation.com/content/189213/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Perhaps surprisingly, it’s possible to get swimmer’s ear without a dip in the pool, lake or ocean. Two doctors explain what this painful infection is and how to get rid of it.Thomas Schrepfer, Assistant Professor of Pediatric Otolaryngology, University of FloridaRex Haberman, Associate Clinical Professor of Otology and Neurotology, University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1664612021-09-21T12:35:00Z2021-09-21T12:35:00ZA pediatrician explains a spike in ear infections this summer after COVID-19 restrictions lifted<figure><img src="https://images.theconversation.com/files/417094/original/file-20210819-23-1xk7q00.jpg?ixlib=rb-1.1.0&rect=0%2C221%2C6709%2C4225&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">With a beam of light, an otoscope allows a clinician to examine the ear canal and eardrum.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/let-me-see-in-your-ear-royalty-free-image/878336612?adppopup=true">SolStock/E+ via Getty Images</a></span></figcaption></figure><p>Ear pain is one of the most common reasons that young children go to the doctor, and acute otitis media – which means “middle ear infection” – is the <a href="https://doi.org/10.1001/jamapediatrics.2013.3924">most frequent cause for the use of antibiotics</a> in children under 5 years of age. Twenty-five percent of children will <a href="https://doi.org/10.1001/jamapediatrics.2013.3924">have an ear infection</a> by their first birthday, and 60% by age 5.</p>
<p>As a <a href="https://uvahealth.com/findadoctor/profile/abigail-v-kumral">pediatrician</a>, I see children in my clinic daily for ear infections. Because these are associated with viral upper respiratory infections, we typically see most ear infections in the fall and winter, when influenza and cold viruses are prevalent. However, with near-universal mask-wearing due to COVID-19 last winter and many children out of school, the number of <a href="https://doi.org/10.1017/ice.2021.303">viral upper respiratory infections dropped drastically</a>. As a result, we saw very few ear infections in our clinic. </p>
<p><a href="https://www.cdc.gov/surveillance/nrevss/rsv/natl-trend.html">This summer</a>, with the lifting of COVID-19 restrictions, we have seen <a href="https://emergency.cdc.gov/han/2021/han00443.asp">a return of many respiratory viruses</a>, and with them, middle ear infections.</p>
<h2>How an ear gets infected</h2>
<p>The middle ear space, which is the space behind the ear drum, is connected to the back of the throat via the eustachian tube. When people, especially children, get congested, they tend to collect fluid in this space. </p>
<p>If a child has a cold and stays congested for awhile, that buildup of fluid can become infected, usually by bacteria that have migrated from the back of the nose or the throat. As children grow, their skull lengthens, and the eustachian tube can drain more easily because it begins to slant downward toward the back of the throat. Over time, children also build immunity to common cold viruses and get sick less often, so overall ear infections decrease with age.</p>
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<img alt="diagram of whole ear with inset of middle ear" src="https://images.theconversation.com/files/419313/original/file-20210903-23-f1m8yf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/419313/original/file-20210903-23-f1m8yf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=546&fit=crop&dpr=1 600w, https://images.theconversation.com/files/419313/original/file-20210903-23-f1m8yf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=546&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/419313/original/file-20210903-23-f1m8yf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=546&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/419313/original/file-20210903-23-f1m8yf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=686&fit=crop&dpr=1 754w, https://images.theconversation.com/files/419313/original/file-20210903-23-f1m8yf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=686&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/419313/original/file-20210903-23-f1m8yf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=686&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">A diagram of the middle ear.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/middle-ear-three-ossicles-malleus-incus-and-royalty-free-illustration/1143768118?adppopup=true">ttsz/iStock via Getty Images</a></span>
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<p>The three most common bacteria that cause middle ear infections are <em>Haemophilus influenzae</em>, <em>Streptococcus pneumoniae</em> and <em>Moraxella catarrhalis</em>. </p>
<p>Interestingly, before we had pneumococcal vaccines against <em>Streptococcus pneumoniae</em>, these bacteria caused about <a href="https://doi.org/10.1097/00006454-200211000-00007">60%-70% of all ear infections</a> in children between 6 months and 5 years of age. But after these vaccines were added to the <a href="https://www.historyofvaccines.org/content/blog/childhood-pneumococcal-vaccine-updated">childhood immunization series</a> in 2001, overall <a href="https://doi.org/10.1542/peds.2017-0181">rates of ear infections dropped</a>, and the proportion due to strep pneumo has gradually decreased to 15%-25%. <em>Haemophilus influenzae</em> now causes the majority of ear infections. </p>
<h2>Guidelines for diagnosing and treating</h2>
<p>The American Academy of Pediatrics’ most recent guidelines for acute otitis media, which is <a href="https://doi.org/10.1542/peds.2012-3488">diagnosed by physical exam</a>, came out in 2013. A doctor will look in a child’s ears with an instrument called an otoscope to see if the ear drum is red or bulging or if it has fluid behind it. Sometimes the doctor will use a small puff of air in the ear to see if the ear drum moves well. If there is an infection behind the ear drum, it will not move with the air. </p>
<p>Acute otitis media is typically treated with antibiotics, which are generally recommended for ear infections in children younger than age 2. For children over 2, antibiotics are recommended if there is a fever or severe pain, or if both ears are infected. In the absence of fever or if the infection is on only one side, the recommendation is to wait a day or two before starting antibiotics, as sometimes these infections will clear on their own in older children.</p>
<p>This differs from treatment for outer ear infections – otitis externa, or “swimmer’s ear” – which can be treated directly with antibiotic ear drops. When the ear canal is very swollen, a wick of gauze may be used to carefully get the antibiotic drops deeper into the ear canal.</p>
<h2>How to prevent ear infections</h2>
<p>Following recommended childhood vaccination schedules is a big part of preventing ear infections, or at least decreasing their frequency. Pneumococcal vaccines are particularly important. Ear infections are a common complication of influenza in children; <a href="https://doi.org/10.1086/424527">about 40% of children</a> younger than 3 years get an ear infection with the flu. So getting a flu vaccine each year can also help prevent ear infections.</p>
<p><a href="https://doi.org/10.1111/apa.13151">Breastfeeding</a> has also <a href="https://doi.org/10.1542/peds.2015-3555">been shown</a> to be <a href="https://doi.org/10.1016/j.jinf.2010.03.034">protective against ear infections</a>, with exclusive breastfeeding for the first six months <a href="https://doi.org/10.1111/apa.13151">providing the most protection</a>. Higher levels of <a href="https://doi.org/10.1111/apa.13151">protective antibodies in breastfed infants</a> as well as immunologic factors found in breast milk help provide this protection. </p>
<p>[<em>Like what you’ve read? Want more?</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=likethis">Sign up for The Conversation’s daily newsletter</a>.]</p>
<p>Children who are exposed to more viral upper respiratory infections are at increased risk for ear infections. <a href="https://doi.org/10.1016/j.jinf.2010.03.034">Children in group day care</a> settings are exposed to more infections, and thus have higher rates of ear infections. That being said, as the mother of a child who loves his day care, it is important to note that group child care is often the most affordable or the only option for families, so it is unclear if day care avoidance is really possible. Since ear infections are much less common in older children, school is less of a risk than day care.</p>
<p><a href="https://doi.org/10.1093/clinids/22.6.1079">Exposure to tobacco smoke</a> is also a risk factor. Caregivers’ quitting smoking when possible and minimizing children’s exposure to tobacco smoke reduce the risk of ear infections.</p>
<p>Some children get ear tubes to help prevent recurrent ear infections. If your child has had at least three ear infections in six months, or four in a year, your pediatrician might refer you to an ear, nose and throat doctor to decide if this surgery would be beneficial for your child.</p><img src="https://counter.theconversation.com/content/166461/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Abigail Kumral does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>With mask-wearing and kids out of school last winter, viral upper respiratory infections decreased. However, clinicians have seen a return of respiratory viruses this summer and ear infections are up too.Abigail Kumral, Assistant Professor of Pediatrics, University of VirginiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1027732018-12-09T19:08:17Z2018-12-09T19:08:17ZHow researchers assess whether medications work<figure><img src="https://images.theconversation.com/files/248953/original/file-20181205-186073-byqw7c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ear infections are no fun. The OSTRICH clinical trial looked at whether oral steroid medications might help. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/view-abovebaby-crying-bed-before-bedtime-772323976?src=awe6dqAVYr9zrU9frzOTyA-1-22">from www.shutterstock.com </a></span></figcaption></figure><p><em>This article is in the series <a href="https://theconversation.com/au/topics/this-is-research-61770">This is research</a>, where we ask academics to share and discuss open access articles that reveal important aspects of science. Today’s piece explains how clinical trials assess drug effectiveness.</em></p>
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<p>Ear infections, or “<a href="https://www.childrens.health.qld.gov.au/fact-sheet-middle-ear-disease/">otitis media</a>”, can cause of a lot of pain and discomfort in youngsters. In some children, persistent infections result in hearing loss. </p>
<p>But what sort of treatment should these children have, and how can doctors work out what is actually effective? </p>
<p>Here’s where a type of research called a clinical trial is useful. </p>
<p>Let’s take a look at the “<a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)31490-9/fulltext">OSTRICH</a>” clinical trial, which investigated the impact of a short course of oral steroids (prednisolone) in children with persistent ear infection leading to fluid build-up in the ear, and hearing loss. </p>
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Read more:
<a href="https://theconversation.com/bulging-ear-drums-and-hearing-loss-aboriginal-kids-have-the-highest-otitis-media-rates-in-the-world-64165">Bulging ear drums and hearing loss: Aboriginal kids have the highest otitis media rates in the world</a>
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<h2>What is a clinical trial?</h2>
<p>Clinical trials are the favoured type of study for showing cause and effect. They sit near the top of the study <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3124652/">pecking order</a>, only outdone in importance by summaries of lots of clinical trials put together. </p>
<p>Clinical trials can assess impact of a medication on a disease or condition. Researchers generally test a particular treatment, and compare the outcome to a different treatment or no treatment (if it’s ethical to do so). </p>
<p>The ideal design is one when the researchers and participants do not know who is assigned to the different treatments being tested. This is referred to as blinding. </p>
<p>Blinding may not always be possible. In food trials for example (where we do most of our work), it is very hard to blind a participant from a food they need to eat. Measures can be taken to minimise the impact of this, though.</p>
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Read more:
<a href="https://theconversation.com/randomised-control-trials-what-makes-them-the-gold-standard-in-medical-research-78913">Randomised control trials: what makes them the gold standard in medical research?</a>
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<h2>The OSTRICH trial</h2>
<p>The OSTRICH trial used an approach where they tested a real medication, in this case a steroid, and compared it to a treatment that was almost the same but without the active ingredient – called a placebo. </p>
<p>The researchers worked with 389 children aged two to eight years with ear infection symptoms, fluid build up for at least three months, and with confirmed hearing loss in both ears. Two hundred kids were allocated to received oral steroids, and 189 to receive placebo for seven days. </p>
<p>With this approach they recorded the impact of the treatments on the ear canal and middle ear, and also conducted clinical tests for hearing. The parents kept a diary of symptoms, and completed questionnaires.</p>
<p>The children were followed up five weeks weeks, six months and 12 months after completion of the treatment. The primary outcome for the trial was acceptable hearing confirmed by an <a href="https://medlineplus.gov/ency/article/003341.htm">audiometry test</a> at five weeks. </p>
<p>Both the families and the researchers did not know who had the real medication until the study was finished – this is called double blinding. This time period meant that researchers had to be careful with the information they collected to avoid <a href="http://ebooks.iospress.nl/volumearticle/40076">potential errors</a>. </p>
<h2>Kids are unpredictable</h2>
<p>Even with the best laid plans, children are hard to predict. As well as looking at the effect of a medication on a disease, the number of study participants who follow all instructions and finish the study as per the plan is an important outcome. </p>
<p>Not all of the starting 389 kids finished the full 12 months of the OSTRICH trial, and this was due to a variety of reasons. Some families withdrew consent to take part, some children didn’t meet the hearing loss criteria at the outset, and some families couldn’t be contacted as time moved on. Some children didn’t always take their medication. This won’t surprise you if you have ever needed to give a child medicine – of any sort. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/249122/original/file-20181205-186055-11fqaje.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/249122/original/file-20181205-186055-11fqaje.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/249122/original/file-20181205-186055-11fqaje.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1066&fit=crop&dpr=1 600w, https://images.theconversation.com/files/249122/original/file-20181205-186055-11fqaje.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1066&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/249122/original/file-20181205-186055-11fqaje.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1066&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/249122/original/file-20181205-186055-11fqaje.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1339&fit=crop&dpr=1 754w, https://images.theconversation.com/files/249122/original/file-20181205-186055-11fqaje.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1339&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/249122/original/file-20181205-186055-11fqaje.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1339&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lots of things happen during a clinical trial that reduce your sample size.</span>
<span class="attribution"><a class="source" href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)31490-9/fulltext">Francis and colleagues, Lancet Volume 392, Issue 10147, p557-568, August 18, 2018</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>In children who did complete the trial, the results showed no statistically significant difference between children treated with the steroid and those treated with the placebo drug. Assessed at five weeks, hearing was only slightly improved in the group assigned the real medication compared to the group given the placebo. </p>
<p>The study authors wrote: </p>
<blockquote>
<p>A short course of oral prednisolone is not an effective treatment for most children aged 2–8 years with persistent otitis media with effusion, but is well tolerated. One in 14 children might achieve improved hearing but not quality of life. </p>
</blockquote>
<h2>What didn’t they find?</h2>
<p>Clinical trials can only make conclusions regarding the effect of what they are testing on the group they have tested it with. </p>
<p>This study quite simply shows that in children aged two to eight, a one-week course of oral steroids has minimal impact on hearing loss in children who had hearing loss due to ear infection and fluid build up, and assessed five weeks after the treatment started. </p>
<p>The study authors can’t conclude that this same finding will apply to children outside of the two- to eight-year age group, or to other types of medications, or steroids given for different time periods. </p>
<p>The researchers commented at the end of their study report that perhaps a clinical trial of oral steroids plus antibiotics is required for children with infection and hearing loss in this age group. </p>
<hr>
<p><em><a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)31490-9/fulltext">The open access research paper for this analysis is Oral steroids for resolution of otitis media with effusion in children (OSTRICH): a double-blinded, placebo-controlled randomised trial</a>.</em></p><img src="https://counter.theconversation.com/content/102773/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Yasmine Probst receives funding from the NSW Ministry of Health and has been an investigator on previously published clinical trials with the Smart Foods Centre, University of Wollongong. </span></em></p><p class="fine-print"><em><span>Lauren Houston conducted this research with the support of the Australian Government Research Training Program Scholarship.</span></em></p>Clinical trials can assess impact of a medication on a disease. The ideal design is ‘blind’ – when the researchers and participants do not know who is assigned to the different treatments.Yasmine Probst, Senior lecturer, School of Medicine, University of WollongongLauren Houston, PhD Candidate, University of WollongongLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/903102018-03-01T19:18:22Z2018-03-01T19:18:22ZExplainer: what are middle ear infections and how are they treated?<figure><img src="https://images.theconversation.com/files/208189/original/file-20180227-36680-nl3sv7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">For some children, ear infections will become a persistent problem.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/crying-baby-close-shot-1034090173?src=5cJN4pvDOhFZhWnqy8hGyQ-1-1">Shutterstock/bookzv</a></span></figcaption></figure><p>Middle ear infections (otitis media) are a common and often painful condition that most children will experience at least once in their first year.
The infection takes hold when a <a href="https://www.ncbi.nlm.nih.gov/pubmed/25434680">bacteria or virus</a> invades the middle ear. </p>
<p>Babies aged <a href="https://www.ncbi.nlm.nih.gov/pubmed/2732519">six to 12 months</a> are <a href="https://www.ncbi.nlm.nih.gov/pubmed/23905821">particularly susceptible</a> because their immune systems have yet to develop the ability to mount a defence against the offending bugs. </p>
<p>Babies’ Eustachian tubes – which drain fluid from the middle ear and the throat – are also not fully developed. This allows bacteria to build up rather than be removed from the ear. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/208187/original/file-20180227-36696-6zssq9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/208187/original/file-20180227-36696-6zssq9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/208187/original/file-20180227-36696-6zssq9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=520&fit=crop&dpr=1 600w, https://images.theconversation.com/files/208187/original/file-20180227-36696-6zssq9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=520&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/208187/original/file-20180227-36696-6zssq9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=520&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/208187/original/file-20180227-36696-6zssq9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=653&fit=crop&dpr=1 754w, https://images.theconversation.com/files/208187/original/file-20180227-36696-6zssq9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=653&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/208187/original/file-20180227-36696-6zssq9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=653&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Babies’ Eustachian tubes aren’t fully developed.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com">Shutterstock/Alila Medical Media</a></span>
</figcaption>
</figure>
<p>With treatment and monitoring, most children will recover quickly. But for some, ear infections will become a persistent problem. </p>
<h2>Symptoms and treatment</h2>
<p>It can be difficult to know if your child is suffering an ear infection. Common signs are pulling at their ears, irritability, fever and lack of appetite. Older children may complain that their ears are sore but it can be difficult to detect in younger children.</p>
<p>Ear infections often occur along with a cold, so children may also have a cough, runny nose or sore throat.</p>
<p>If your child is in a significant amount of pain, get their ears checked by your GP. The doctor will recommend some pain relief and ask you to monitor the condition at home for around 48 hours, by which time most acute ear infections have subsided. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/bulging-ear-drums-and-hearing-loss-aboriginal-kids-have-the-highest-otitis-media-rates-in-the-world-64165">Bulging ear drums and hearing loss: Aboriginal kids have the highest otitis media rates in the world</a>
</strong>
</em>
</p>
<hr>
<p>If your child suffers repeated ear infections (more than three within six months, or more than four in a year) the doctor is likely to refer you to an ear, nose and throat (ENT) specialist. </p>
<p>If there is runny fluid or pus coming from their ear, it’s important to seek treatment as soon as possible, even if that means going to the <a href="http://kidshealthwa.com/guidelines/otitis-media/">emergency department</a>. Usually the pus will be removed, the ear cleaned out, and antibiotic drops prescribed. Follow-up assessments with audiologists (allied health hearing specialists) and ENT doctors will be arranged to check their hearing and if the ear drum has healed. </p>
<p>Some types of ear infections are asymptomatic, meaning there is no pain or discomfort, but the child may have problems hearing.</p>
<p>If left untreated, ear infections can cause developmental delays. So, if you are concerned about your child’s ears or hearing, even if there is no obvious sign of infection, it is important to get their ears checked.</p>
<h2>The problem with recurring infections</h2>
<p><a href="https://www.ncbi.nlm.nih.gov/m/pubmed/25303240">Our study</a> found that more than one quarter of children have had recurring middle ear infections by the time they are three years of age. Having recurring ear infections in infancy <a href="http://www.tandfonline.com/doi/abs/10.1080/13575279.2017.1403889">dramatically increases the risk</a> of having ongoing problems with ear infections throughout childhood.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/my-child-has-glue-ear-what-do-i-do-83815">My child has glue ear – what do I do?</a>
</strong>
</em>
</p>
<hr>
<p>This can cause <a href="https://www.ncbi.nlm.nih.gov/pubmed/23906989">hearing loss</a> and impact on <a href="http://pediatrics.aappublications.org/content/106/4/725.short">school readiness</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/2387994">performance in class</a>, <a href="https://www.tandfonline.com/doi/abs/10.1080/21695717.2017.1325094">mental health</a> and overall <a href="https://www.ncbi.nlm.nih.gov/pubmed/24627408">quality of life</a>. </p>
<p>Hearing loss as a result of ear infections can also persist into adulthood. The effects get worse with age and hearing <a href="https://www.ncbi.nlm.nih.gov/pubmed/25401378">declines at a faster rate than those without recurrent ear infections</a>. </p>
<h2>How to reduce the risk</h2>
<p>Keeping children’s vaccinations up-to-date is important for reducing the risk of ear infections and many other diseases. The introduction of the PCV-13 pneumococcal vaccine for all children at two, four and six months of age has resulted in a <a href="https://www.ncbi.nlm.nih.gov/pubmed/25159581">dramatic reduction</a> in middle ear infections. </p>
<p>For those who are able to, breastfeeding is another way. Breast milk contains antibodies to some of the bacteria that cause ear infections. Exclusive breastfeeding for more than four months has been <a href="https://www.ncbi.nlm.nih.gov/m/pubmed/25303240/">found</a> to decrease the risk of ear infections. </p>
<p>Focusing on wiping runny noses and washing hands (after going to the toilet, before eating, after changing nappies, and after wiping noses) can <a href="https://www.ncbi.nlm.nih.gov/pubmed/10742313">reduce</a> the spread of infections. Parents and carers can also teach these good hygiene practices to children. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/cleaning-your-hands-may-be-more-complicated-than-you-think-26315">Cleaning your hands may be more complicated than you think </a>
</strong>
</em>
</p>
<hr>
<p>Good infection control practices are especially important for young children with <a href="https://www.ncbi.nlm.nih.gov/m/pubmed/25303240/">older siblings</a>, those who live in <a href="https://www.ncbi.nlm.nih.gov/pubmed/21593705">overcrowded living conditions</a>, and for those who <a href="http://www.tandfonline.com/doi/abs/10.1080/13575279.2017.1403889">attend childcare centres</a>, where the risk of ear infections is higher.</p>
<p>Parents should keep children with active ear infections away from other children, including from school and childcare centres, as much as possible until they are well.</p>
<p>If you’re unsure whether your child has an ear infection, or if it has returned, talk to your GP so it can be identified and treated early.</p><img src="https://counter.theconversation.com/content/90310/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brad Farrant receives funding from the NHMRC. </span></em></p><p class="fine-print"><em><span>Chris Brennan-Jones receives research funding from the NHMRC and the Western Australian Department of Health. </span></em></p>Middle ear infections (otitis media) are a common and often painful condition that
most children will experience at least once in their first year.Brad Farrant, Adjunct Research Fellow in Early Childhood Development, The University of Western AustraliaChris Brennan-Jones, NHMRC Health Professional Research Fellow, Telethon Kids Institute, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/858542017-10-18T08:51:29Z2017-10-18T08:51:29ZNew research shows some children who struggle to read or write may actually have hearing problems<figure><img src="https://images.theconversation.com/files/190622/original/file-20171017-30417-1dwkj2d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">shutterstock</span></span></figcaption></figure><p>Ear infections are the number one reason for preschool <a href="https://www.nidcd.nih.gov/health/ear-infections-children">children to visit the GP</a>. Ear infections can be painful, cause difficulty with balance and can also lead to temporary hearing loss. </p>
<p>Most parents assume that there will be no long lasting effects once an ear infection clears up – and most of the time this is true. But in some cases, children can become permanently deaf after repeated infections – which is also known as “<a href="http://www.nhs.uk/Conditions/Glue-ear/Pages/Introduction.aspx">glue ear</a>”.</p>
<p>It seems that repeated ear infections can also increase the risk of reading difficulties – as our <a href="http://www.nuffieldfoundation.org/sites/default/files/files/Morphological%20processing%20in%20children%20with%20phonological%20difficulties%20executive%20summary(1).pdf">recent study</a> shows. We found that a third of children who had repeated ear infections had <a href="https://doi.org/10.1111/desc.12588">reading difficulties at age nine</a>. </p>
<p>In <a href="https://doi.org/10.1111/desc.12588">another group of children</a>, we also found that a quarter of children with reading difficulties in year four of school had some degree of deafness that their parents and <a href="http://www.nuffieldfoundation.org/sites/default/files/files/Morphological%20processing%20in%20children%20with%20phonological%20difficulties%20executive%20summary(1).pdf">teachers were not aware of</a>.</p>
<h2>The link between hearing and reading</h2>
<p>Most children who have reading difficulties are <a href="http://www.nuffieldfoundation.org/sites/default/files/files/Morphological%20processing%20in%20children%20with%20phonological%20difficulties%20executive%20summary(1).pdf">not deaf or hard of hearing</a> – but there is a significant overlap. </p>
<p>This is because learning to read builds on a child’s <a href="http://www.ican.org.uk/%7E/media/Ican2/What%20We%20Do/Enquiry%20Service/Language-and-literacy-fact-sheet.ashx">existing knowledge</a> of language. So children who can’t always hear speech well can find it harder to work out how spoken words “map” onto printed words. </p>
<p>In this way, learning to read can be <a href="https://theconversation.com/new-strategy-needed-for-deaf-children-with-reading-difficulties-23394">difficult for children who are deaf</a>. Even mild deafness can have a <a href="http://www.ndcs.org.uk/family_support/positive_parenting_families/family_stories/mild_deafness.html">big impact on hearing</a>. And children with mild or moderate deafness can also have trouble understanding conversation in busy environments – like the classroom.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/190624/original/file-20171017-30379-13ef4wg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/190624/original/file-20171017-30379-13ef4wg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/190624/original/file-20171017-30379-13ef4wg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/190624/original/file-20171017-30379-13ef4wg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/190624/original/file-20171017-30379-13ef4wg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/190624/original/file-20171017-30379-13ef4wg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/190624/original/file-20171017-30379-13ef4wg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Children struggling to read or write may have undetected hearing problems.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>That said, the link between hearing and reading difficulties isn’t inevitable – not all deaf children <a href="http://www.city.ac.uk/__data/assets/pdf_file/0014/212441/Briefing-paper-Reading-and-dyslexia-in-oral-deaf-children-website-final-version-feb-2014.pdf">struggle to read</a>. This is because learning to read involves the combination of many different skills – such as understanding the link between letters and speech sounds, knowledge of grammar, memory for spelling patterns and the use of context. And all of those skills can help children to learn to read and write effectively, even if they do initially have difficulty.</p>
<h2>Testing times</h2>
<p>All newborn babies have their <a href="https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/506078/NHSP_screening_pathway_-_well_baby_with_dual_branding.pdf">hearing screened in the UK</a>, and the government’s “healthy child” <a href="https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/492086/HCP_5_to_19.pdf">policy</a> also recommends hearing screens when children start school. </p>
<p>These policies have dramatically increased early identification for deaf children. But school entry hearing screens are <a href="https://njl-admin.nihr.ac.uk/document/download/2001486">not offered in all areas of the UK</a>. And because of funding cuts, services are even being <a href="http://democracy.somerset.gov.uk/documents/s1527/Proposed%20Decommissioning%20of%20the%20School%20Hearing%20Screening%20Service.pdf">withdrawn in some places</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/190623/original/file-20171017-30381-nr3m2l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/190623/original/file-20171017-30381-nr3m2l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/190623/original/file-20171017-30381-nr3m2l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/190623/original/file-20171017-30381-nr3m2l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/190623/original/file-20171017-30381-nr3m2l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/190623/original/file-20171017-30381-nr3m2l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/190623/original/file-20171017-30381-nr3m2l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Around a third of the children who had repeated ear infections had problems with reading and writing.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>When you consider that around half of the 50,000 deaf children in the UK were not born deaf but <a href="https://www.actiononhearingloss.org.uk/about-us/our-research-and-evidence/facts-and-figures/">lost their hearing during childhood</a>, it is easy to see how these children
– with mild, fluctuating or acquired deafness – can be missed by existing screening procedures. And this of course then makes them more at risk of poorer literacy outcomes. </p>
<h2>Supporting reading</h2>
<p>It is clear then that children who have difficulty learning to read should have current and past hearing test results taken into account. These children should also be <a href="http://www.nhs.uk/Conditions/Hearing-and-vision-tests-for-children/Pages/Introduction.aspx#children">reassessed where appropriate</a>, so that both doctors and teachers – as well as parents – can work together to help that child.</p>
<p>This is important, because children who have had a lot of ear infections have been found to have very specific difficulties with perception of speech sounds. And in most cases, other <a href="http://dx.doi.org/10.1080/10888438.2016.1246554">reading</a> and <a href="http://dx.doi.org/10.1017/S0142716416000072">spelling</a> related skills are not impaired. </p>
<p>What this means, is that parents and teachers could not only provide extra support to help these children understand the links between letters and sounds, but they can also use those other skills to support their reading – enabling them to <a href="http://www.ndcs.org.uk/family_support/education_for_deaf_children/education_during_school_years/developing_reading.html#contentblock1">reach their full potential</a>.</p><img src="https://counter.theconversation.com/content/85854/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Helen L Breadmore has received funding from The Nuffield Foundation. The Nuffield Foundation is an endowed charitable trust that aims to improve social well-being in the widest sense. It funds research and innovation in education and social policy and also works to build capacity in education, science and social science research. The Nuffield Foundation has funded some of this research, but the views expressed are those of the authors and not necessarily those of the Foundation. More information is available at <a href="http://www.nuffieldfoundation.org">www.nuffieldfoundation.org</a></span></em></p>Should children with reading difficulties get their hearing checked?Helen L Breadmore, Research Fellow in Child Development and Education, Coventry UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/713042017-08-22T01:58:59Z2017-08-22T01:58:59ZSome nerves: How loud noise may change hearing<figure><img src="https://images.theconversation.com/files/182480/original/file-20170817-28120-3lx528.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Hearing can be affected by loud noises, but the mechanisms have not been fully understood. The auditory nerve plays a big role.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-suffers-hearing-impairment-hard-loss-199580039?src=TSBUGYly2U2GRT3vFIKXJg-1-13">9nang/Shutterstock.com</a></span></figcaption></figure><p>Our modern world is loud. Just sitting in a car, or an airplane, or watching movie previews, we are bombarded with sound. Even when those noises aren’t damaging to the sensitive microphone that is our ear, our auditory system is constantly activated. What are the consequences of this?</p>
<p>One reason noise is a problem is that it is associated with tinnitus. Tinnitus, or ringing in the ears, is very common, affecting about <a href="http://onlinelibrary.wiley.com/doi/10.1002/ajim.22565/abstract">10 percent of the population</a>. For some people, it can be severe enough to interfere with everyday life. </p>
<p>The sensation of ringing seems to originate in the brain, <a href="http://www.nejm.org/doi/full/10.1056/NEJMra013395">not in the ear </a>. But where does that mistaken activity start, and is there any way of stopping it? If we can determine the origin, it might help us figure out ways to prevent or cure tinnitus.</p>
<p>Understanding how the auditory system deals with loud noise would have big implications, because we are all regularly exposed to loud sounds, sometimes for extended periods.</p>
<p>I am a researcher studying the very first place that activity from the ear enters the brain. My students and I became interested in these questions because we have long wondered how the auditory system deals with loud environments.</p>
<h2>Running down the synapse</h2>
<p>We expected that loud noise would deplete an essential component to the hearing process. That essential component is located at the connections between nerve cells, which are called <a href="https://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0024276/">synapses</a>. In hearing, synapses are critical gatekeepers for transmitting information about sounds from the ear to the brain. Synapses work when an electrical impulse in one cell triggers the release of little packets of chemicals, called neurotransmitters, that cause electrical changes in the next cell across the synapse. </p>
<p>Those packets of neurotransmitter take some time to be replenished. That means that if brain cells carrying information from the ear are highly active, the neurotransmitter could get used up, so there would not be enough to activate their targets in the brain, and the signal would get lost.</p>
<p>This is a particular issue when the signals occur faster than the synapse can restock. For cells in the auditory system, this could be a real problem, because they experience among the fastest rates of activity, especially when they are subjected to intense sound.</p>
<p>So how do we continue to hear in loud environments, if our synapses can run out of neurotransmitter?</p>
<h2>Adapting to loud</h2>
<p>To explore this, we put mice in a loud environment for about a week. The noise was as loud as a hair dryer, enough to drive the auditory system without damaging the ear appreciably. </p>
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<img alt="" src="https://images.theconversation.com/files/182481/original/file-20170817-9185-qynvh8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/182481/original/file-20170817-9185-qynvh8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/182481/original/file-20170817-9185-qynvh8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/182481/original/file-20170817-9185-qynvh8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/182481/original/file-20170817-9185-qynvh8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/182481/original/file-20170817-9185-qynvh8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/182481/original/file-20170817-9185-qynvh8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The author’s study examined the effect of noise on mice’s hearing.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/head-mouse-macro-164346473?src=spb77noK9vroVSEr-hT9ow-2-13">Schankz/Shutterstock.com</a></span>
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<p>At the end of the week, we looked at changes in synapses formed by the auditory nerve, which carries signals from the ear into the brain. <a href="http://www.pnas.org/content/112/20/6479.full">The synapses changed</a> from the normal situation of getting rapidly depleted of neurotransmitter to hardly depleting at all. </p>
<p>The synapses also got bigger and increased their stockpiles of neurotransmitter. Both these changes could protect synapses from running out of neurotransmitter when activity levels are high. Indeed, we found that after noise exposure, nerve impulses increased their success of being transmitted across the synapse, when normally they often fail to do so.</p>
<p>This idea of adapting to activity is familiar, like how muscles bulk up after working out. But it was not known that synapses in the brain sense their activity too. This raises lots of questions about how it works.</p>
<p>These changes seem beneficial while the animal remains in loud noise, but what happens after returning to normal quiet conditions? We found that the synapses changed back to normal when mice were returned to quiet conditions, but this appears to take several hours or days. </p>
<p>So, immediately after returning to a quiet environment, the synapse would be overprepared and wouldn’t run out of neurotransmitter like normal. This could cause hyperactivation of auditory nerve targets in the brain, which could be perceived as sound even in the absence of sound, which is tinnitus. </p>
<p>My own experience is that my tinnitus gets worse after a long airplane or car trip. One possibility is that my synapses are adapting to the loud sound conditions, which causes hyperactivity after the trip ends. To see how even limited noise exposure leads to tinnitus, we have just begun a collaboration with Micheal Dent and her lab, because they are experts in the hearing abilities of mice. These studies in mice may help us to understand if this is an unrecognized risk factor for tinnitus in humans.</p>
<h2>Adapting to quiet</h2>
<p>This study also made us wonder: If loud noise causes synaptic changes, what about decreases in sound? Small children commonly experience <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2948776/">decreases in sound</a>, because about half of them experience an ear infection, usually in their first two years. Ear infections lead to a buildup of fluid behind the eardrum, which reduces the ability of sound to get from the external part of the ear to the business end tucked inside. </p>
<p>For some kids, there can be long-term consequences of sound deprivation, where they have trouble <a href="http://link.springer.com/article/10.1007%2Fs10162-011-0271-6">processing language</a>.</p>
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<img alt="" src="https://images.theconversation.com/files/182482/original/file-20170817-28163-15vnmf2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/182482/original/file-20170817-28163-15vnmf2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/182482/original/file-20170817-28163-15vnmf2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/182482/original/file-20170817-28163-15vnmf2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/182482/original/file-20170817-28163-15vnmf2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/182482/original/file-20170817-28163-15vnmf2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/182482/original/file-20170817-28163-15vnmf2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Ear infections in children can sometimes cause long-term problems.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/doctor-using-otoscope-instrument-check-girls-673639543?src=iCfSCrYkhdTBtBOVJn1crg-1-33">Andrey_Popov/Shutterstock.com</a></span>
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</figure>
<p>It is still unclear how the brain is changed by sound deprivation at these early ages, and how it could lead to processing problems as the children grow up.</p>
<p>We have started to examine how auditory nerve synapses in mice are affected when their ears are <a href="http://www.jneurosci.org/content/37/2/323.long">plugged</a>. Interestingly, we saw the opposite of what happened with noise. After one week’s plugging, the synapses got smaller, and the stores of neurotransmitter shrank, leading to even faster depletion than normal. </p>
<p>We think these changes help maximize efficiency. A large stock of unused neurotransmitter would be wasteful when activity is low, so the synapse can shrink. Also, low activity means synapses would have more time to replenish minimal neurotransmitter stores between bouts of signaling.</p>
<p>After noise exposure ended or ears were unplugged, the synapses recovered to normal. That seems like good news, but we can’t be sure yet there are not some small residual effects that might become clearer with more experiments. Also, multiple rounds of noise exposure or plugging could cause residual effects to accumulate.</p>
<p>This prompted me to think about my own family. My daughter was prone to ear infections when she was little. It seemed that every few months we would go to the pediatrician, who would wait until there was visible buildup of fluid behind the eardrum before prescribing antibiotics to cure the infection. This is understandable, because of concern about overuse of antibiotics causing resistance. </p>
<p>But when these episodes would occur, we never actually tested my daughter’s hearing to know the extent or duration of hearing loss. Now I know that her auditory nerve synapses were likely changing. Did any of these changes become permanent? I don’t think she has problems processing language, but I wonder about other aspects of auditory processing.</p>
<p>This work gives us new appreciation for auditory nerve synapses. They have been thought of as machines whose job was to relay information dependably. Now we know that job is not so simple after all. The synapses are continually assessing their activity and adjusting themselves to optimize and economize their performance. We think these changes or ones like them at other synapses could lead to long-term consequences for tinnitus and language processing.</p><img src="https://counter.theconversation.com/content/71304/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Xu-Friedman receives funding from the National Science Foundation and the National Institute of Deafness and Communication Disorders. A student who conducted some of the work described, Tenzin Ngodup, received support from the Dalai Lama Trust Fund.
</span></em></p>Noise is common, but we don’t fully know what that means for our hearing. A recent study suggests how overstimulation of the auditory nerve may be too much for it to handle.Matthew Xu-Friedman, Associate Professor of Biology, University at BuffaloLicensed as Creative Commons – attribution, no derivatives.